We want to encourage those of you who ENJOY our site and find it USEFUL to DONATE and UPGRADE your membership from active member to donating or premium membership. If you want to know the differences in membership benefits, please visit THIS PAGE:

Donating memberships start at just $10 per year. These memberships are in fact donations that help pay our costs, and keep our site running!
Thank you for your donation, God Bless You

As some of you know, I have wanted to stop managing H-M for some time.
It's a tremendous strain on my personal life. I want to set up my own shop.
In September, September 15, to be exact, it will be 8 years that Hobby-Machinist has been in existence.

I have been training VTCNC to run things here. Dabbler is going to learn too.
I feel that they are ready to start taking over the operation.
I will be here to help in case they need, but I don't think they will.
Tony Wells is and will be here also to consult with.
I will be doing backups, upgrades, and installing addons.
Other than that, I will not be around.
I am leaving this place in good operating condition, and financial condition.
--Nelson

Registered

Well, I scored one on eBay... I have a parts list and cross section, and only a couple of missing parts. Does anyone out there have one? I am having a hard time understanding what the little pistons are supposed to do. They seem to do some sort of venting function, but I can't see why they are there! Are the air passages so small that it cycles super slowly?
Thanks,
WeldingRod

Registered

I looked at the drawing and thought about it a LOT more (sligthly hampered by by flu-addled brain)... It turns out that the little cylinder and poppets are pilot operated check valve. When you pressurize the open port, the close side of the cylinder is opened to the close air port by one little cylinder pushing open its check valve; this lets the close air out. The open air side flows past its check valve until the open side is at full air pressure. Once the air flow stops, the open side check valve closes. The key thing is that the air is TRAPPED in the air cylinder! You can turn off the air supply completely after this! So, it doesn't really matter that the Hardinge swivel thing leaks like crazy; you don't need to keep it presurized.